GALVESTON, Texas -- The Coast Guard partially reopened one of the nation's busiest seaports to ship traffic Tuesday, three days after a collision between a barge and a ship spilled up to 170,000 gallons of tar-like oil into the waters south of Houston.
Authorities said ships were being allowed through the Houston Ship Channel after their assessment teams deemed it was clear enough for passage. More than 100 ships on both sides of the channel were awaiting the reopening.
"The cleanup operations progress is to the point that there is minimal danger of contamination to the commercial maritime traffic and allowing limited transit during daylight hours," said Coast Guard Capt. Brian Penoyer. "This is an important accomplishment for every person working this response."
The oil spill happened Saturday, when a barge carrying 900,000 gallons collided with a ship, leading to the closure. Traffic through the channel includes ships serving refineries key to American oil production.
The amount of oil spilled was much less than such major U.S. disasters as the 1989 Exxon Valdez disaster in Alaska, which dumped 11 million gallons of oil into the Prince William Sound, and the Deepwater Horizon spill, which resulted in 100 million gallons of oil entering the Gulf of Mexico four years ago.
Officials believe most of the oil that spilled Saturday is drifting out of the Houston Ship Channel into the Gulf of Mexico, which should limit the impact on bird habitats around Galveston Bay as well as beaches and fisheries important to tourists.
The best-case scenario is for most of the slick to remain in the Gulf for at least several days and congeal into small tar balls that wash up further south on the Texas coast, where they could be picked up and removed, said Jerry Patterson, commissioner of the Texas General Land Office, the lead state agency on the response to the spill. Crews from the General Land Office are monitoring water currents and the movement of the oil, he said.
Patterson said he saw "very little" oil sheen on the bay waters during a flyover Tuesday morning.
"The big question is, 'Where is the oil that went into the Gulf of Mexico?'" he said in a phone interview. "That's the next question to be answered."
Environmental groups said the spill occurred at an especially sensitive time and place. The channel in Texas City, about 45 miles southeast of Houston, has shorebird habitat on both sides, and tens of thousands of wintering birds are still in the area.
At least 50 birds of six species have needed treatment due to the oil, said Richard Gibbons, conservation director of the Houston Audubon Society. The species include sanderling, ruddy turnstone and the American white pelican, Gibbons said.
The channel, part of the Port of Houston, typically handles as many as 80 large ships, as well as about 300 to 400 tugboats and barges.Crews have laid down miles of oil boom and have been picking up black, quarter-sized "tar balls" washing up on shore. Cannons are being blasted on one beach to scare birds from the oil-slicked sand and rocks. The oil has been particularly difficult to clean up, said Rich Arnhart of the state's response team.
"It's just a thicker oil, it stays together and doesn't evaporate as fast as some of the lighter crude oils or lighter fuel oils," he told CBS News.
At Galveston Island, a popular tourist destination due to its beaches and parks, crews have laid booms around environmentally sensitive areas.
Some black, tar-like globs, and a dark line of a sticky, oily substance, could be seen along the shoreline of the Texas City dike, a 5-mile jetty that juts into Galveston Bay across from a tip of Galveston Island.
In Texas City, near several refineries, crews picked tar balls out of the sand and set up cannons that boomed every few minutes to scare off birds.
At Galveston's East Beach, workers set up metal posts to hang lines of absorbent material to collect tar balls as they washed up. On the other side of a jetty, crews were scooping oil from the sand and pouring it into plastic bags.
"It's very hard to tell how long we'll be out here," Coast Guard Petty Officer Richard Forte said.
Jim Guidry, executive vice president of Houston-based Kirby Inland Marine Corp., which owned the barge, has said the company - the nation's largest operator of inland barges - would pay for the cleanup.